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The facile synthesis of biografted 2D derivatives complemented by a nuanced understanding of their properties are keystones for advancements in biosensing technologies. Herein, we thoroughly examine the feasibility of aminated graphene as a platform for the covalent conjugation of monoclonal antibodies towards human IgG immunoglobulins. Applying core-level spectroscopy methods, namely X-ray photoelectron and absorption spectroscopies, we delve into the chemistry and its effect on the electronic structure of the aminated graphene prior to and after the immobilization of monoclonal antibodies. Furthermore, the alterations in the morphology of the graphene layers upon the applied derivatization protocols are assessed by electron microscopy techniques. Chemiresistive biosensors composed of the aerosol-deposited layers of the aminated graphene with the conjugated antibodies are fabricated and tested, demonstrating a selective response towards IgM immunoglobulins with a limit of detection as low as 10 pg/mL. Taken together, these findings advance and outline graphene derivatives’ application in biosensing as well as hint at the features of the alterations of graphene morphology and physics upon its functionalization and further covalent grafting by biomolecules.

Here, we have thoroughly studied the effect of chemistry of graphene derivatives on the composition of N-species after N-doping with the help of core-level spectroscopy techniques. The modulation of the N-species by tailoring the functionalization and atomic structure of graphene derivatives prior to chemical N-doping is experimentally demonstrated for the first time. The large extent of non-terminated or phenol-functionalized graphene edges is found to facilitate the formation of pyridinic nitrogen with its relative content exceeding 72%. In turn, the predominant decoration by the pyrazolic moieties is shown for the perforated and carboxyl-derived graphene layers. The thermal annealing at moderate temperatures of ca.345 °C is shown to equally readjust the composition of N-species in graphene derivatives regardless of their chemistry, nanostructure, and the initial distribution of the N-species. Further examination of N K-edge X-ray absorption spectra (XAS) pointed out that the oxidation of the graphene layer governs the manifestation of the π∗ resonances and configuration of the σ∗ resonance. As a result, a set of facile methods to synthesize graphene derivatives with the desired type of the embedded nitrogen species for the optoelectronic and catalytic applications are proposed and crucial features of their identification using core-level spectroscopy techniques are emphasized.

Here, the synthesis of holey carbonylated (C-ny) graphene derivative and its application for gas sensing is demonstrated. The carbonylation of graphene oxide leads to the 3-fold increase in the concentration of carbonyl groups’ up to 9 at.% with a substantial elimination of other oxygen functionalities. Such a chemical modification is accompanied by the perforation of the graphene layer with the appearance of matrices of nanoscale holes, leading to corrugation of the layer and its sectioning into localized domains of the π-conjugated network. Combined with the predominant presence of carbonyls, granting the specificity in gas molecules adsorption, these features result in the enhanced gas sensing properties of C-ny graphene at room temperature with a selective response to NH3. Opposite chemiresistive response towards ammonia when compared to other analytes, such as ethanol, acetone, CO2, is demonstrated for the C-ny graphene layer both in humid and dry air background. Moreover, a selective discrimination of all of the studied analytes is further approached by employing a vector signal generated by C-ny multielectrode chip. Comparing the experimental results with the calculations performed in framework of density functional theory, we clarify the effect of partial charge transfer caused by water and ammonia adsorption on the chemiresistive response.

A mathematical model is formulated, and a numerical study of magneto-plasma compressor (MPC) discharges in gases for a wide range of changes in the main electrical parameters and the characteristics of the surrounding gas environment is carried out. The performed calculations showed, depending on the role of one or another heating mode (Ohmic, transient, and plasma dynamic), three different types of quasi-stationary spatial distributions of plasma parameters, which can be used to judge the features of the emerging structures and the dynamics of plasma propagation, and, therefore, to speak about the modes of discharge. The features of the radiation plasma dynamic structures and the change in the main parameters of the plasma of an MPC discharge in the transient regime are considered.

A review of theoretical and experimental studies in the field of compression and heating of a plasma target in an external magnetic field, which has recently been called magneto-inertial fusion (MIF), has been carried out. MIF is a concept of magnetically driven inertial fusion that involves the magnetization of fuel, laser pre-heating, and magnetic implosion to create fusion conditions. An analysis of the current state of work on the implosion of magnetized targets and the effect of an external magnetic field on the main plasma parameters and system characteristics is presented. Questions regarding the numerical simulation of experiments on the magnetic-inertial confinement of plasma are touched upon. Particular attention is paid to two promising areas of MIF—with plasma jets and with a laser driver (laser beams).

The main purpose of this article is to study the features of the structure and spectral brightness characteristics of pulsed emitting discharges of the magneto plasma compressor type in dense gases over a wide range of energy–power parameters. A numerical simulation of plasma dynamic magneto plasma compressor discharge in gases is carried out. Different quasi-stationary regimes have been studied and the main characteristics have been estimated.

The one-step method for graphene oxide (GO) simultaneous reduction and carboxylation via ultraviolet irradiation in the inert atmosphere has been reported. X-ray photoelectron spectroscopy (XPS) an...

A numerical model to calculate the heat transfer and resistance coefficients near the bodies of complex geometric shapes moving at high velocity is formulated. The processes of heat and mass transfer and flow around aircraft elements are considered. An algorithm for calculating heat fluxes and the heat transfer coefficient is proposed. The developed numerical technique can give an idea of the essential features of the flow, heat transfer at the end keels of the wings, and integral layouts of high-speed aircraft. An approximate mathematical model for calculating the heat transfer processes and resistance coefficients near the bodies of complex geometric shapes moving at high speed in the Earth’s atmosphere is formulated. The calculated results for convective heat transfer and friction coefficients for the X-33 and X-43 vehicles are obtained.

Graphene derivatization to either engineer its physical and chemical properties or overcome the problem of the facile synthesis of nanographenes is a subject of significant attention in the nanomaterials research community. In this paper, we propose a facile and scalable method for the synthesis of thiolated graphene via a two-step liquid-phase treatment of graphene oxide (GO). Employing the core-level methods, the introduction of up to 5.1 at.% of thiols is indicated with the simultaneous rise of the C/O ratio to 16.8. The crumpling of the graphene layer upon thiolation without its perforation is pointed out by microscopic and Raman studies. The conductance of thiolated graphene is revealed to be driven by the Mott hopping mechanism with the sheet resistance values of 2.15 kΩ/sq and dependable on the environment. The preliminary results on the chemiresistive effect of these films upon exposure to ethanol vapors in the mix with dry and humid air are shown. Finally, the work function value and valence band structure of thiolated graphene are analyzed. Taken together, the developed method and findings of the morphology and physics of the thiolated graphene guide the further application of this derivative in energy storage, sensing devices, and smart materials.

In this paper, we for the first time demonstrate efficient nitrogen doping of graphene oxide (GO) with nitrogen concentration of up to 5 at.% via modified Hummers' method. Using X-ray photoelectron spectroscopy (XPS), X-ray absorbance spectroscopy (XAS) and Fourier transform infrared spectroscopy (FTIR) techniques, we have found out graphitic nitrogen to be the dominant type of the implemented nitrogen species. At the same time, the subsequent GO thermal reduction to graphene appears to result in a transformation of the graphitic nitrogen into pyridines and pyrroles. The mechanisms of the observed GO nitrogen doping and conversion of the nitrogen species are proposed, providing an opportunity to control the type and concentration of the implemented nitrogen within the approach. A two-time increase of the graphenes' conductivity is observed due to the performed nitrogen doping. Further comprehensive electrical studies combined with the transmission electron microscopy (TEM) and density functional theory (DFT) modeling have allowed us to estimate the conductivity mechanism and the impact of the implemented nitrogen. As a net result, a simple method to synthesize N-doped graphene with the desired type of the nitrogen species is developed, which leads to new perspective applications for graphene, i.e. supercapacitors, catalysis, and sensors.

The present work reports on compact toroid hydrogen plasma creation by means of a specially designed discharge system and results of magnetic fields introduction. Experiments in the compact toroid challenge (CTC) device at P.N. Lebedev Physical Institute (FIAN) have been conducted since 2005. The CTC device differs from the conventional theta-pinch formation in the use of an axial current for enhanced efficiency. We have used a novel technique to maximize the flux linked to the plasma. The purpose of this method is to increase the energy input into the plasma and the level of trapped magnetic flux using an additional toroidal magnetic field. A study of compact torus formation with axial and toroidal currents was done and a new method is proposed and implemented.

This paper deals with the analysis of the possible use of magneto-inertial fusion (MIF) to create a neutron source. We consider the configuration of the target in the form of an axially symmetric m...

The compact torus/toroid (CT) as future fusion reactor is presented. The field reversed configuration (FRC) is alternative thermonuclear scheme with properties of compact tori as both open and closed systems. By plasma confinement method field reversed configuration is closed magnetic trap. Mathematical model of plasma core in the fusion reactor is shown. Power balance for the FRC confinement chamber is calculated. The formula for bremsstrahlung more accurate in the temperature range of advanced fuel is presented. D- 3 He- 6 Li fuel cycle is proposed and reactor schemes are discussed.

Field reversed configurations (FRC), 1,2,3 as mirror machines have been developed as simple plasma confinement systems. FRC formed by reversing of magnetic field and reconnection and sustained by plasma current. Several mirrors may be linked together with solenoids - tandem mirrors (TM), end losses in the axisymmetric tandem mirror are reduced by ambipolar trapping - ambipolar trap (AT). Power balance of deuterium - helium-3 (D- 3 He) plasma in a prolate FRC power plant is compared with the power balance for a central cell of D- 3 He tandem mirror reactor (ambipolar trap). Deuterium - tritium (D-T) ITER 4 , kinetically stabilized tandem mirror (KSTM)5 and D- 3 He FRC5 parameters are demonstrated.

Magnetic geometries like the field reversed configuration and spheromak are compact toroids, where plasma is enclosed in a linear external magnetic field geometry. To burn advanced fuels requires a high fusion power density compact system and a D- 3 He field reversed configuration will be considered here. Such innovative confinement concept together with remarkable advantages of compact system and advanced fuels, including direct energy conversion, full lifetime fusion core, fusion space propulsion, nonelectrical application of D- 3 He fusion energy and space resources including helium-3 fusion fuel is very attractive.

The high fusion power density resulting from high beta (the ratio of the plasma to magnetic energy density) and natural divertor make the field-reversed configuration (FRC) a prime candidate for fusion reactor other than tokamak, the so-called alternate concept. Brief review of the simple compact system with natural advantages and reactor potential is given. Theoretical and experimental results over the last seven years are discussed.

A numerical model of ion kinetics is considered for the axially symmetrical magnetic trap. The trap contains warm Maxwellian plasma and strongly non-Maxwellian high-energy (fast) ions. The steady-s...